CASE STUDY
Highlighted Project
Multi-facet Installation
Oxford, UNITED KINGDOM
OVERVIEW
Special focus: Different slopes
Installer: Engensa
Installation date: 17 Nov. 2010
Location: Oxford, UK
Average Irradiance:
1120 kWh/m2/year
Installed Capacity: 3.3kWp
Modules: 18 x 185W ET Solar
Power optimisers:
18 x PB250-AOB
Inverters: 1 x SE3300
On November 17th 2010, Engensa, a
leading British installer of PV systems,
installed a 3.3 kWp PV installation on
the roof of a property in Oxford, UK. The
owner of the property, Mr. Bakewell, is
already familiar with solar technology. As
the owner of a swimming pool business
and a supporter of green technology,
he promotes the use of solar heating
installations to keep the pool water
warm. His beautiful old estate, bathed by
the scent of the surrounding pine trees,
serves as an exhibition space for his
pools. To improve his carbon footprint
even further Mr. Bakewell wanted to
install a grid-connected PV system on
his house.
“When I first consulted a PV professional
about installing a grid-connected PV
installation, I explained to them that I had
two houses at about 10 meter distance
from each other, both of which have a
south facing roof facet. The professional
recommended that I install two PV
installations using two inverters, one
for each roof” says Mr. Bakewell. The
problem was that the roofs of the two
houses have two different slopes: one
has a 25˚ slope and the other has a 40˚
slope.
A 3.3 kWp installation consisting of one string with 18 modules that spreads across two roofs with two
different slopes: 25° and 40°. The string is connected to a SolarEdge SE3300 inverter.
“They also said that my pine trees could
pose a problem because they cast shades
on my home in the mornings.”
Traditional
installation
habits
recommend avoiding shaded areas on
the roof and stick to rather rigid design
rules: strings connected to the same
inverter need to be identical in length,
orientation and slope, as do modules
in a serial connection. Hence, in their
efforts to avoid mismatch between
modules, installers are limited in their
freedom to design PV systems the way
they would ideally like to.
The surprise came when Mr. Bakewell
called Engensa for a second opinion.
He found it was actually possible
to install one PV system that would
spread across the two roofs using
a SolarEdge inverter and SolarEdge
power optimisers. The installed system
consists of one SolarEdge SE3300
inverter, 18 185W ET Solar modules,
and 18 SolarEdge PB250-AOB power
optimisers connected together in one
string spanning the two different roofs.
Power optimisers are attached to each
module separately and track their
individual Maximum Power Point. The
MPPT is optimal at all times regardless
of the mismatch between the modules.
www.SolarEdge.cominfo@solaredge.com
To sum up: installers who work with
traditional inverter systems are limited
in their ability to design tailor-made PV
systems and have to use complicated,
and often costly, installation strategies.
Engensa has been working with
SolarEdge for a while now and offers
its technological advancements to
break through existing boundaries.
SolarEdge enables the installation
of PV systems with optimal energy
output regardless of the amount of
partial shade. The SolarEdge power
optimisers also maintain a fixed string
voltage that extends the maximum
string length. These advantages are of
particular importance in the UK, where it
is very common to install on a group of
neighbouring row house rooftops.
“SolarEdge’s
product
is
the
breakthrough that we have been
waiting for. Providing our customers
with the best innovations on the market
whilst maintaining reliability and value
are central to Engensa’s company
strategy. SolarEdge is the only product
of its type that we trust, due to their
unparalleled track record and longer
warranty conditions.”
Dr Toby Ferenczi
CTO Engensa